Block 2

• neural crest differentiate into?

  • Cranial nerve ganglia
  • Dorsal root ganglia
  • Autonomic ganglia cells
  • Mesencephalic nucleus of midbrain
  • Enteric neurons
  • Adrenal medullary cells
  • Chromaffin cells
  • Schwann cells
  • Melanocytes
  • Meninges (Pia and Arachnoid)
• When does the neuropore close?

  Day 28
• Which embryonic part is the cerebellum derived from?

  Metencephalon
• Alar plate (Dorsal-Sensory) induced by BMP
• Basal plate (Ventral-Motor) induced by SHH
• Myelination of the CNS Pre-natally:

  Myelination begins by about the 4th month (16th week) in the cervical spinal cord

  Myelination in the brain begins by the 6 month (basal ganglia)
• Myelination of the CNS Post-natally:

  • Corticospinal tract begins myelination in the 6th month post-natally
  • Spinal cord myelination continues for years–At least until the age of 2.5 – 3 years old
• What is responsible for Babinski response in infants?

  Corticospinal tracts are not fully myelinated, takes about 6 months
• Anencephaly - Failure of closure of anterior neuropore with gross associated problems in cranial bones and skin (Day 25-28)

  
• Anencephaly is caused by folic acid deficiency
• Meningocele - protrusion of meninges
• Meningomyelocele - protrusion of meninges with nerves
• Myelocele - protruding nerve mass with no covering – the worst type of cystica
• Why is the germinal matrix so important?

  Hemorrhage of placenta during second trimester can cause major underdevelopment of part of the cerebral cortex
• Dandy-Walker Syndrome

  • Cerebellar agenesis (partial or complete) – usually Vermis
  • Dilated 4th ventricle
  • Hydrocephalus
  • agenesis of corpus callosum

  
• Cerebral Palsy - Spastic – muscle tightness, hypertonicity

  • Upper motor neuron lesions and GABAergic receptor dysfunction
  • treatment antispasmodic meds such as botulinum toxin and baclofen
• Cerebral Palsy Ataxic - cerebellar damage causes difficulty with coordination of muscle movements and balance.
• Cerebral Palsy Athetoid (Dyskinetic) - damage to basal ganglia, or just substantia nigra
• 2 subtype of Athetoid (Dyskinetic) cerebral palsy

  • Choreoathetoid ADCP – involuntary movements in face and extremities
  • Dystonic ADCP – strong, slow contractions, whole body or local
•   Primary nociceptor induction - Direct mechanical activation
•   Primary nociceptor induction

  • Causes tissue damage
  • Induces low pH
  • synthesis of prostaglandins (PG) and bradykinin (BK)
  • release of K
• Sympathetic = Prevertebral Ganglia via Splanchnic Nerves
• Parasympathetic = Cranial work is via Vagus and Sacral work is via Pelvic Splanchnic Nerves
• What would stimulate glucagon release?

  Beta 2 receptors
• Alar plate

  • dorsal aspect
  • induced by BMPs (bone morphogenetic proteins)
  • forms sensory track neurons
• Basal plate

  • ventral aspect
  • Neurons in Lateral Horn and ventral horn
  • induced by SHH
  • forms motor and preganglionic

     autonomic neurons
• Gray Matter Heterotopia

  • Failure of cortical cells to migrate to final position
  • Caused by interruption in Germinal Matrix during second trimester
• Lissencephaly - Failure of cortical cells to migrate to final position in germinal matrix
• Syringomyelia - associated damage to fibers of the spinothalamic tract
• Horner’s syndrome is Sympathetic was c8-t1 via ventral root
• When you see the pyramids, that means you are heading towards the ventral horns (going down)
• kid having diarrhea which means a stomach virus and then it will be the polio and then the causative agent is Polio - what symptoms do they have?


  Areflexic symptom
• Person is having pain somewhere and then gets up a lot at night to pee and then paresthesia - what do they have?

  Tabes dorsalis
• what does Renshaw cells do?

  • tetanus toxins cleave vesicular proteins to prevent release of Renshaw Glycine (and GABA) in spinal cord causing muscle rigidity
  • Inhibition of Glycine Transmission
• Which receptor responds to fast vibration?

  Pacinian
• Pain in thumb that is quite severe then it goes up to elbow, how did it happen?

  Silent Nociceptor Recruitment
• Question about pain and rubbing, what circuit is responsible for it

  Inhibitory Interneuron (dorsal horn)
• Referred pain is likely caused by Convergence of cutaneous afferents and pain afferents on the same 2nd order neuron on dorsal horn
• Tic Deloreaux caused by Superior cerebellar artery CN5
• locus ceruleus could inhibit neuron directly